This is the conclusion (Part 5) of my series on iPhone apps that track calories in and calories out. As discussed previously, there are many different apps available, but other than user reviews posted in the app store, there’s currently limited help available to determine which one will work best for you. Over the past month, I’ve provided detailed reviews of several traditional diet diary apps: Lose it!, MyFitnessPal, DailyBurn and SparkPeople. I also reviewed two other apps, PhotoCalorie and Diet Tracker Lite that take a different approach to tracking food intake by using photos. Can apps such as these serve as effective feedback and be a useful tool to promote weight loss? Does adherence to self-monitoring increase with an electronic diary versus keeping a paper journal?

A recent study by Lora Burke and colleagues published in Obesity reports on the initial results of the SMART (self monitoring and recording using technology) trial.(1) This is the first study to examine how a portable electronic device with self-monitoring software affects weight loss and dietary intake. Subjects participated in a 24 month behavioural weight loss program to assess the differences between three self-monitoring tools. In addition to receiving daily dietary goals, weekly exercise goals, and regular group sessions, participants were assigned to self-monitor with one of the following options:

The feedback messages received by the third subject group were generated automatically using an algorithm based on each individual’s dietary entries.(1) Subjects received one feedback message per day at a randomly selected time of day

The preliminary results after 6 months of intervention suggest that yes, technology can help! All groups acheived significant weight loss during the first quarter of the study period. The authors report that the combination of using an electronic diet diary and receiving individualized daily feedback is more successful at supporting both weight loss and adherence to self-monitoring compared to the other forms of self-monitoring studied. 63% of subjects using the PDA and receiving personalized daily feedback group lost 5% or more of body weight. This was significantly higher than the other subject groups at 49% (PDA alone) and 46% (paper record).(1)

The median adherence to self monitoring of diet over the 6 month period for subjects using the PDA plus personalized feedback was also the highest of the three groups at 90%. For subjects using the PDA alone, the median adherence was slightly less at 80%, but was only 55% in subjects using a paper record. Adherence for all groups peaked during the second week of the study and declined in all groups over the initial 6 months of the study. A similar pattern was observed for self-monitoring of physical activity.(1)

Although adherence was higher in both groups using the PDA to track caloric consumption and expenditure, why was the group receiving personalized feedback more successful in achieving weight loss? The authors note that “feedback…enhances motivation towards goal attainment“.(1) From a systems perspective, tailoring the information to be specific to an individual’s entries may enable the participant to identify it as something important to them, making the feedback self-determined and thus more effective. Additionally, these messages also reduce delay in the feedback loop – a subject does not need to wait for the weekly group meeting to receive recommendations from a health care practitioner that were based on the previous week’s entries. Daily messages allow the subject to make adjustments to diet at the next meal or adjust the current day’s exercise plans to ensure both dietary and exercise goals are met each day.

The authors conclude that an electronic diet and exercise diary may help improve adherence to self-monitoring, and if paired with individually tailored feedback, may also help improve weight loss success.(1) How does this knowledge apply to my current review of iPhone apps? It helps identifies which features of calorie counting apps will best support behaviour change, and allows us to provide a more useful evaluation of these apps.

The chart below summarizes select features we believe important for providing successful feedback, including factors that facilitate ease of use (e.g. accessible instructions, quick data entry, ability to correct errors) and functions that enable personalized feedback (e.g. daily goal setting, graphing of results over time, and customised reminders). (Note that just a few apps are reviewed here.)

Unfortunately, all of the apps share two common weaknesses: all require multiple steps to enter foods and none provide the opportunity to receive individually tailored reminders or feedback messages. Cumbersome data entry may cause some users to discontinue using the program. Some apps do offer short cuts for favourite foods or meals, though it may take time to establish these.

Most apps also provide a indicator of net calories remaining each day. This shows progress towards the set daily goal and allows the user to adjust their behaviour in a timely manner. Some apps send a daily email newletter or a reminder to check-in, but the content is not tailored specifically to the individual. By simplifying data entry and delivering personalized feedback, app developers have the opportunity to enhance the effectiveness of their apps in supporting successful behaviour change.